[R] Newbie on functions

[Angelo Secchi]

Hi,
I'm trying to write a simple function like

case1 <- function (m, cov, Q, R) {
  theta     <- (acos(R/sqrt(Q^3)))
  beta      <- (-2)*sqrt(Q)*cos(theta/3)+m[1]/3
  rho1      <- (-2)*sqrt(Q)*cos((theta+2*pi)/3)+m[1]/3
  rho2     <- (-2)*sqrt(Q)*cos((theta-2*pi)/3)+m[1]/3
  stderrb   <-  deltamethod( ~(-2)*sqrt(Q)*cos(theta/3)+x1/3,m,cov)
  stderrr1  <-  deltamethod( ~(-2)*sqrt(Q)*cos((theta+2*pi)/3)+x1/3, m,
cov) stderrr2  <-  deltamethod( ~(-2)*sqrt(Q)*cos((theta-2*pi)/3)+x1/3,
m, cov) stderr    <- c(stderrb,stderrr1,stderrr2)
  results   <- c(beta,rho1,rho2,stderr)
  results2  <- t(results)
  results2
}

When I call the function in an IF statement like

if (Q^3>R^2) results2 <- case1() else print('ciccio')

I get 

Error in eval(expr, envir, enclos) : Object "theta" not found

I do not understand why, any help?
Thanks


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 Angelo Secchi                     PGP Key ID:EA280337